Why is my CO2 flow rate so high?

jhoeger

New member
Hi all,
Like so many in our hobby, my passion "waned" after a mechanical failure caused me to lose every coral and invert in my 140 gallon mature reef tank (with refugium) a couple of years ago. I lost literally thousands of dollars worth of LPS, and soft corals. I had so many mushrooms that I was trading them to my LFS in exchange for other corals. I almost considered getting rid of everything I had, after losing coral that had thrived for almost 20 years. But after several years of having a FOWLR tank, I couldn't accept "reef defeat", and decided to re-dedicate myself to becoming the best "reef daddy" my wallet and attention to detail would allow.

After finding a "great deal" on a used Korallin C3002 calcium reactor, I was finally ready to provide the calcium level required for a successful LPS and SPS environment, that didn't have to depend on my religious dedication to add Turbo Calcium on a regular schedule (which I really sucked at). If I paid the same attention to my dog's daily nutritional needs, as I had been to my coral's needs, my dog would probably have died, and I'd be prosecuted for cruelty to animals.
Now that lack of proper equipment was no longer my excuse, I researched everything I could find on setting up my calcium reactor for maximum performance. In order to set it up the way I wanted it, I needed to buy; a new Maxijet 1200 powerhead to use as a feed pump (I had to locate the reactor approximately 10 feet away from the tank, into my laundry room, causing a 22' run of 1/4" ice maker line), an Eheim 1048 circulation pump, 2 gallons of extra course Caribsea A.R.M. Aragonite Reactor Media (filled to the proper level in the regulator), 2 new Milwaukee SMS122 PH controllers (both calibrated to 7.01 levels), a new Milwaukee MA957 CO2 regulator set-up with solenoid shut off, a new 10# aluminum CO2 tank (just filled with CO2 from a fire extinguisher company), and 75' of plastic 1/4" ice maker distribution line from Home Depot (3x25').

After making sure that there were no kinks in any of the lines, I dropped the feed pump into the return section of my sump, and followed the Korallin installation instructions to the letter. I adjusted the effluent drip rate to 40 drops/minute, while still having a nice even "over flow" rate from the reactor.

I initially started the CO2 at 8-10 bubbles/minute (as indicated on the Korallin bubble counter, not the CO2 regulator glass bottle). That rate of CO2 didn't budge the PH more than .1 from the PH of the tank itself (as measured by another new "PH Calibrated" Milwaukee SMS122 PH controller).

In order to get the PH level in the reactor to 6.7, I have had to increase the bubble rate to almost 60 bpm. At that rate, I can get the PH low enough (6.6) to turn off the CO2. The effluent calcium level measures at 440 on an API calcium test kit, with a PH of 7.8. Pre-installation, my tanks PH measured between 8.0 and 8.3, with a calcium level of 380 (achieved with irregular use of Turbo Calcium). The tanks post-installation PH rate is between 7.9 and 8.1. After about a week of adjusting the CO2 rate, not allowing it to run during the night (just in case it causes my PH to plummet while I'm sleeping), the tanks calcium rate is 400.

I purchased a used American Marine Pinpoint ORP controller, and my new probe is coming in by the end of the week. It didn't come with a probe, so I have no idea what the ORP rate is. "Eye-balling" the tank tells me that I'm on the right track, because my LPS corals are fully inflated and look like they are thriving, not just surviving. I am keeping my salinity rate at 1.023, at a temperature of 78-79 degrees with the help of a chiller.

I cannot find any "free" CO2 inside the reactor, and am considering "aerating" the effluent in an overflow container to reduce the PH, if the tanks PH level continues to decrease.

Should I be concerned about the amount of CO2 that I am using right now? Other forums seem to indicate that others are achieving proper calcium levels at much, much lower CO2 rates. Am I doing something wrong? Any suggestions?

I've tried to provide as many details as possible, to help assess whatever the problem(s) are/is. Many of you will say that I "over killed" the question with information, but I've asked enough questions in the past to know that in order to get the help I need, you need to know where I'm at, and what I'm doing.

Thanks so much for the help. I've been at this hobby for over 35 years, but understand that there are many of you that are less than half my age that have already forgotten more than I know. I look forward to your suggestions, and am prepared for your criticisms (as long as they are constructive).

Note: Knowledge shared between dedicated hobbyist helps everyone, most especially those unlucky creatures "snatched" from their natural environment in the name of commerce, that rely on us being able to provide a new "home" that allows them to "thrive", instead of merely "survive".

Jim H.
 
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Does your reactor capture and recirculate injected CO2? Some reactors do, and it definitely cuts down on the amount of gas needed. Though you said you couldn't find any free CO2 in the reactor, so that may not factor in.

We buy our CO2 from a gas supply company and not a fire extinguisher company. Anybody know the purity of either?

What is the ALK of your effluent? I've heard optimal is 25-30 dKH. Try slowing the effluent rate of the reactor to bump up the concentration of dissolved material. You can either aerate your effluent or plumb it into a second chamber with reaction media.
 
I'm not sure about the recirculation of CO2. I'm pretty confident about the CO2 quality, because of the type and size of the company I went to. But then, I could be wrong.
I'll check the Dkh of the effluent, and re-post my results. I agree that the CA level should be higher if I'm "melting" the aragonite with a PH of 6.7, so I'll check that again as well, and re-post.

Thanks for responding so fast,

Jim H
 
FWIW we didn't get good dissolution of our media (dKH above 20) until we lowered the reactor pH to about 6.0. This is probably due to the type of media we're using and/or our high effluent rate not allowing adequate contact time with the media to achieve saturation.

All I know is that 2L of media at a pH of 6 and effluent rate of 60-90dpm is not enough to keep up with a very demanding T. gigas :debi:
 
Several people have had issues with dissolution of the ARM extra coarse media, especially in smaller reactors.
 
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